headplane/app/server/headscale/api/factory.ts

import type { HeadscaleApiInterface } from "../api";

/**
 * Creates a strongly-typed group factory for a given endpoint interface.
 *
 * Example:
 *   export const apiKeyGroup = defineGroup<ApiKeyEndpoints>({...})
 */

export interface EndpointFactory<T extends object> {
  __type?: T;
  (client: HeadscaleApiInterface["clientHelpers"], apiKey: string): T;
}

export function defineApiEndpoints<T extends object>(
  factories: (client: HeadscaleApiInterface["clientHelpers"], apiKey: string) => T,
): EndpointFactory<T> {
  return factories;
}

export type ExtractApiEndpoints<F> = F extends EndpointFactory<infer T> ? T : never;
export type UnionToIntersection<U> = (U extends any ? (k: U) => void : never) extends (
  k: infer I,
) => void
  ? I
  : never;

/**
 * Compose multiple endpoint sets into a single typed runtime client
 */
export function composeEndpoints<T extends readonly EndpointFactory<any>[]>(
  factories: T,
  clientHelpers: any,
  apiKey: string,
): UnionToIntersection<ExtractApiEndpoints<T[number]>> {
  const instances = factories.map((f) => f(clientHelpers, apiKey));
  return Object.assign({}, ...instances) as any;
}